16mm or 25mm

[Ponty Massive]

I've recently relocated a new consumer unit, went to the local wholesalers and they did not have 25mm tails in stock. As it's a 60A main fuse (TN-S) I thought 16mm would suffice so happily installed them.

Just checking through the OSG P17 (2.2.3) and it states minimum cable size should be 25mm?



What's your input chaps??

 

[marksparky]

iv no problem installin 16mm tails if u check ur osg i think 16mm is fine up 2 82amps clipped direct, i think the 25mm is allowing for future additions and possible fuse upgrade, ur dno will also specify size of tails required, although im in ni (we work 2 same regs) they always specify 16mm

 

[SirKit Breaker]

16mm is fine for your application. Most, myself included fit 25mm as the norm, for the reasons stated by marksparky.

 

[SirKit Breaker]

I've recently relocated a new consumer unit, went to the local wholesalers and they did not have 25mm tails in stock. As it's a 60A main fuse (TN-S) I thought 16mm would suffice so happily installed them.

Just checking through the OSG P17 (2.2.3) and it states minimum cable size should be 25mm?



What's your input chaps??

If your local wholesaler hasnt got them, all the big sheds stock them usually as a kit with a 16mm earth chucked in, they are a bit pricey but gets you out of a corner.

 

[Ponty Massive]

Think I'll change them to 25's tomorrow. Using it as my assessment so want to get it spot on.

Also, I know it's been covered a thousand times but....The new board is positioned up high above the meter in the hallway. I've run the tails in the cavity and clipped them for support in the loft (it's a bungalow), is this ok aswell?

 

[Des 56]

He will unlikely question the route of the tails

If it was me,I would have no problem with the tails in the cavity
Others on here see terrible deeds being done with this age old practice

16mm is not a requirement for consumer units,it is a guide used when calculation of cable size may be difficult for the installer and is a one shoe fits all solution

 

[Ponty Massive]

Thank you all.

 

[Amp David]

I only tend to opt for 16mm if its a 2 way garage CU or similar as the main switch is usually only rated at 63amps and as you not supposed to overload the main switch, alway find 16mm to be fine.

Plus theres never enough space to pull in 25mm tails 99% of the time.